The occurrence of dramatic changes in mood, behavior, cognition and somatic functioning in some women in relation to the menstrual cycle has recently been the focus of a great deal of public scrutiny. This project is designed to study the psychobiology and treatment response of women with well-defined menstrually-related mood disorders. The longitudinal screening methods developed by this group are capable of distinguishing women with menstrually-related mood syndromes from those who only believe that they have such a syndrome. With these methods, we have identified the following: 1) menstrual cycle phase dependent changes in perception and cognitive performance in patients with menstrually-related mood disorders but not controls; 2) an increased tendency to dissociate in patients versus controls; 3) an increased prevalence of abnormal basal and stimulated thyroid measures in patients; 4) a higher than expected frequency of hypoglycemic episodes following glucose tolerance testing in women with premenstrual syndrome irrespective of menstrual cycle phase; and 5) preliminary evidence of the efficacy of alprazolam in the treatment of premenstrual syndrome relative to placebo or other treatments employed. The goals of this project are to detect and accurately describe menstrually-related mood disorders, explore their pathophysiology and response to pharmacological and environmental manipulation, and to document the relationship between reproductive endocrine change and disorders of mood as a way of further investigating the neurobiology of psychiatric illness.